Just to clarify things a little...
The problems David are encountering are not so much with one particular instructor, as with the whole 'school' and the 'character' who runs/owns it - and is also the examiner there.
He is not the first person to have issues at that place - and I am speaking from personal experience.
As I said privately to David, I was advised to take action - but I just wanted to forget about it frankly.
When we have a system which allows the owner, CFI, and examiner to be one and the same person, I'm afraid that this kind of situation is bound to occur from time to time.